package export

import (
	"fmt"

	"rideaware/internal/user"
	"rideaware/internal/workout"
)

type Service struct {
	workoutRepo *workout.Repository
	userRepo    *user.Repository
}

func NewService() *Service {
	return &Service{
		workoutRepo: workout.NewRepository(),
		userRepo:    user.NewRepository(),
	}
}

func (s *Service) ExportFIT(workoutID, userID uint) ([]byte, string, error) {
	w, err := s.workoutRepo.GetWorkoutByID(workoutID, userID)
	if err != nil {
		return nil, "", fmt.Errorf("workout not found: %w", err)
	}

	u, err := s.userRepo.GetUserByID(userID)
	if err != nil {
		return nil, "", fmt.Errorf("user not found: %w", err)
	}

	ftp := 0
	if u.Profile != nil {
		ftp = u.Profile.FTP
	}
	if ftp <= 0 {
		return nil, "", fmt.Errorf("FTP must be set in your profile before exporting FIT files")
	}

	data, err := EncodeFITWorkout(w, ftp)
	if err != nil {
		return nil, "", err
	}

	filename := sanitizeFilename(w.Title) + ".fit"
	return data, filename, nil
}

func (s *Service) ExportZWO(workoutID, userID uint) ([]byte, string, error) {
	w, err := s.workoutRepo.GetWorkoutByID(workoutID, userID)
	if err != nil {
		return nil, "", fmt.Errorf("workout not found: %w", err)
	}

	data, err := GenerateZWO(w)
	if err != nil {
		return nil, "", err
	}

	filename := sanitizeFilename(w.Title) + ".zwo"
	return data, filename, nil
}

func sanitizeFilename(name string) string {
	if name == "" {
		return "workout"
	}
	result := make([]byte, 0, len(name))
	for _, c := range name {
		switch {
		case c >= 'a' && c <= 'z', c >= 'A' && c <= 'Z', c >= '0' && c <= '9':
			result = append(result, byte(c))
		case c == ' ' || c == '-' || c == '_':
			result = append(result, '_')
		}
	}
	if len(result) == 0 {
		return "workout"
	}
	return string(result)
}